Magnetostatic coil in air

[federico]

Hi everyone,
I am new on elmer and i need some help; i am sure someone here can help me .
I am tryng to simulate the magnetic field strength of a coil surrounded by air.. then i would improve my example with another coil.
This because i want to calculate the mutual inductance between the two coils, with a magnetic energy approch, if it is possible.

Here is attached the a screenshot of what i have in elmer.
The geometry is simply a disc in a sphere.

First of all i would like to know if the meshing (i used gmsh) is correct.
Then i would like to know how i have to use some solvers like coilsolver, mgdyn..

Is there anyone who can help me with the compilation of the correct sif file?

Regards
federico

[kevinarden]

examples here
https://github.com/ElmerCSC/elmer-elmag

[raback]

Hi,

Here is a tentative case that automates things for the computation of inductance matrix between several coils. If you work with this I would be happy if you would be in contact since this is work in progress.

-Peter

[federico]

Hi,
thanks for your replies.

About the case you send me, i am not really sure how i can improve the process.

However, i am tryng to open the fivecoils example in elmer to improve my skills, modifyng the geo file with only two torus.

The problem i have is that elmer crushes when i try to load the netgen mesh generated.

How can i load the mesh file of fivecoils in elmer without crush?

thanks for the attention and patience,

regards,
federico

[kevinarden]

It is difficult to tell without your project files. Pictures are of limited value. Best approach is a github repository and share all files your are working with. Then others can collaborate and find potential issues.

[federico]

Sorry, i was not clear.

I am trying to open in Elmer the fivecoils example, out of my beginning study case.

But when i load the fivecoils.geo in netgen and i generate the mesh, i have problem with exporting it and opening in elmer.

If i save the mesh and i open it in elmer, it crashes everytime.

Is there an easier way to open fivecoils example on Elmer?

Regards
federico

[kevinarden]

I was able to do it, but when I just accepted the defaults in netgen it generated over 20,000,000 solid elements.
I changed the settings to very coarse and it generated 6,085,310 tets, 774,160 surface elements.
I exported it as an elmer mesh and elmerGUI was able to open it.

5coil.png

(306.83 KiB) Not downloaded yet

[federico]

Oh thanks for the advice, now it is actually less heavy.

However i am working on my starting case and i obtained this results.

The first problem i have is that i don't know what is the "vortex" generated between the two coils when i calculate the coilcurrent (image attached).
Then i wuold like to see a better uniform distribuition of magnetic flux density and magnetic field strenght.

At last i would calculate the mutual inductance between the two coils.
This is what i have in my mind: i would like to generate a desired corrent only in a coil (1), then with the calculation of the magnetic flux density linked in the second coil (2) i'll calculate the mutual inductance (M=flux linked/current in coil 1).

regards
federico

[raback]

Hi

I could not get this "two_Coils.geo" file to work with my installed Gmsh v. 4.8.4. What version are you using. Maybe you could sent a .msh file.

There are two coils. Then the CoilSolver needs two Component sections to define them. The definitions in the Solver section can only be used for one coil. Just take my example and modify the "Target Bodies" and "Target Boundaries". There are anyways recent stuff not supported by the GUI.

-Peter

[kevinarden]

The mesh 3D option fails with the defaults on the geo file. \if you go to tools, mesh, options, general, and change element size factor to 0.50 it will mesh. \there is no mesh size defintion in the geo.\\